Frequent on-off service Processes where the ”instantly” large flow is needed.
Little resistance to flow
Fully open/xlosed, non-throttling
Minimal fluid trapping in line
Cannot be used for pressure control
Cavitate at low pressure drops
Cannot be used for throttling
Usually made of ASTM A439 D2, for large size of valves rolling bearing is fitted at the two sides of the stem nut un order to minimize the open and close torque of valve.
Handwheel or Gearbox is usually used for gate valve actuation. The chain wheel, pneumatic cylinder, and electric actuator can be also used for the valve actuation if being requested by customer.
Stainless steel + flexible graphite spiral wounded gasket is used for 150 to 600 class, ring joint gasket is also optional for class 600 valves, for class 900 and above pressurized seal design is used.
Die molded pure graphite rings with top and bottom ring of brained graphite with Inconel wire reinforcement
BOBY BONNET CONNECTION
The body&bonnet between cass 150 to 600 bolted bonnet for 900 and above pressure seal design.
Stems are non-rotating with surface finish to maximize packing seal for low fugitive emissions.
All our gate valve have back seat design, carbon steel valves are fitted with the removable back seat for stainless steel integral machined with a bonnet.
Seat faces lapped for a smooth finish and superior sealing. Optional renewable threaded seats or welded seats are as per customer specifications.
Flexible wedge for improved seating ease of operation, specially in high temprature service, wedges are accurately guided thru the entire stroke
Extended Bonnet design for low temperature and cryogenic services.